angular - 如何捕捉 Observable.forkJoin(...) 中的错误？

Question

我使用 Observable.forkJoin() 来处理两个 HTTP 调用完成后的响应，但如果其中任何一个返回错误，我该如何捕获该错误？

Observable.forkJoin(
  this.http.post<any[]>(URL, jsonBody1, postJson) .map((res) => res),
  this.http.post<any[]>(URL, jsonBody2, postJson) .map((res) => res)
)
.subscribe(res => this.handleResponse(res))

Answer 1

您可以捕获传递给forkJoin的每个可观察对象中的错误:

// Imports that support chaining of operators in older versions of RxJS
import {Observable} from 'rxjs/Observable';
import {forkJoin} from 'rxjs/add/observable/forkJoin';
import {of} from 'rxjs/add/observable/of';
import {map} from 'rxjs/add/operator/map';
import {catch} from 'rxjs/add/operator/catch';

// Code with chaining operators in older versions of RxJS
Observable.forkJoin(
  this.http.post<any[]>(URL, jsonBody1, postJson).catch(e => Observable.of('Oops!')),
  this.http.post<any[]>(URL, jsonBody2, postJson).catch(e => Observable.of('Oops!'))
)
.subscribe(res => this.handleResponse(res))

另请注意，如果您使用 RxJS6，则需要使用 catchError 而不是 catch，并使用 pipe 运算符而不是链接。

// Imports in RxJS6
import {forkJoin, of} from 'rxjs';
import {map, catchError} from 'rxjs/operators';

// Code with pipeable operators in RxJS6
forkJoin(
  this.http.post<any[]>(URL, jsonBody1, postJson).pipe(catchError(e => of('Oops!'))),
  this.http.post<any[]>(URL, jsonBody2, postJson).pipe(catchError(e => of('Oops!')))
)
  .subscribe(res => this.handleResponse(res))